A report on Friday sheds new light on a very unique issue Apple is dealing with at its Apple Park campus, saying a Cupertino city officials raised concerns about employees walking into glass doors, panels and walls well before the facility opened this year.

Massive glass doors at Apple Park's cafeteria.

In an interview with the San Francisco Chronicle, Cupertino building official Albert Salvador and Santa Clara County Fire Department representative Dirk Mattern said they brought the potential issue to Apple's attention during a site visit some nine months ago. Specifically, Salvador was concerned employees would walk into the cafeteria's glass walls, into which are integrated large floor-to-ceiling doors.

"We did recognize that this is going to be an issue, especially when they clean the glass," Salvador said. "When you clean the windows, you can't even tell some of them are there."

Underscoring their point, as Salvador and Mattern were discussing the topic with an Apple contractor, another worker walked into a glass wall.

Subsequent injuries have been reported to emergency services. According to information gleaned from a Santa Clara County public records request, three people suffered head injuries while moving into the campus in early January, the report said. 911 audio retrieved in the request reveals one victim was bleeding from their eyebrow after striking a window.

Prior to being granted approval to open, and as a result of Salvador and Mattern's urgings, Apple Park architects Foster + Partners placed black rectangular stickers on the cafeteria's doors. The same markers were put on other clear glass surfaces around the facility's main "spaceship" structure following the January incidents.

The stickers appear to be doing their job, as no further incidents were reported to emergency services following their installation.

The design problem was highlighted in a report earlier this month that noted Apple Park employees were bumping into glass panes separating the collaborative "pods" that make up the facility's interior. Workers had taken to applying sticky notes on clear surfaces, but the markers were supposedly being removed because they detracted from the building's design.

Apple was well aware of the issue. Today's report points to a January statement in which Apple VP of real estate and development Dan Whisenhunt told the Rotary Club of Cupertino that birds flying into the central ring structure's glass walls was not a problem.

"Now, the humans on the inside, that's a different story," Whisenhunt said. "We've had people bump into the glass. That's a problem we are working on right now."